The equation 2 has a graph which is a straight line.
Why?
We can know which of the given equations has a graph which is a straight line just checking the exponents of the variables.
We must remember that every variable that has an exponent equal or higher than 2 (quadratic) will not have a straight line as a graphic.
So, checking the exponents from the given equations, we have:
[tex]Equation_{1} =x^{3}=NotLinear\\Equation_{2}=x=Linear\\Equation_{3}=y^{2}=Quadratic\\Equation_{4}=x^{2}=Quadratic[/tex]
Hence, we can see that the only equation that has a linear term (straight line graph), is the second equation.
Have a nice day!
Note: I have attached a image for better understanding.
